Petroleum product and method of making same



Patented Oct. 20, 1936 UNITED STATES PATENT OFFICE Robert O. Moran,

Wenonah, and William L.

Ever: andEverett W. Fuller, Woodbury, N. J., assignors to Socony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporation of New York No Drawing. Application October 26, 1935, Serial No. 46,870

7 Claims. (01. 87-9) This invention is directed to the stabilization of hydrocarbon oils of higher boiling points against the deteriorating effects of oxidation. Highly refined oils of the non-sludging types, such as the white oils, turbine oils and the like, must be able to withstand the conditions of their use without the formation of acidic constituents of a corrosive or otherwise damaging nature. This invention contemplates the stabilization of such oils. Moderately refined oils of the nature of many lubricant fractions must likewise be able to withstand the conditions of their use without the formation of sludges, loss of color, or development of oxidation products corrosive to commonly used metals, as for instance to copper. This invention likewise contemplates the stabilization of such moderately refined oils. In short, this invention is directed to the stabilization against deterioration due to oxidation reactions of any petroleum fractions of a light lubricant nature or heavier, from the lightest spindle oils, through the various classes of moderately, refined oils of higher viscosity, and inclusive of the highly refined oils such as turbine oils, white oils and the like.

This invention has for an important object the preparation of oils falling within the above classes which are stable against oxidation and capable of meeting the normal conditions of their use without the formation of gummy material, sludges,

materials of an acidic or corrosive nature, and/or darker color. It also has for an object the provision of a class of stabilizing materials not heretofore known to be effective for that purpose.

Recent changes in automotive engine design, tending toward higher bearing pressures, higher rotative speeds, higher engine temperatures, and the like, have occasioned departure from the use of the usual bearing metals such as babbit. The newer bearing metals are of different nature, and while harder, are in general more susceptible to destructive agencies of a corrosive nature. cal of these newer bearings are those composed of a cadmium-silver alloy supported upon a steel back, which are now widely installed in certain makes of automobiles. Others of these relatively new bearing metals which may be mentioned are cadmium-nickel and copper-lead alloys.

These changes in engine design have been concurrent with marked advances in methods of refining lubricant oils for automotive use. The demand for oils having lesser changes in viscosity with temperature change; i. e., higher viscosity index (VI), has been met by refining lubricants intended for motor oils by certain solvent refining or solvent extraction processes, wherein ad- 5 vantage is taken of the selective solvent power for hydrocarbons of various types which is possessed by certain liquid reagents, for example, dichlorodiethylether, cresylic acid, phenol, chloraniline, chlorophenol, phenetidine, benzyl alcohol, nitrol0 benzene, benzonitrile, furfural, aniline, benzyl acetate, liquid sulfur dioxide, mixtures of liquid sulfur dioxide or aniline with benzol, and the like. These solvent refining processes are operated to concentrate in the desired lubricant frac tion those compounds of a paraflinic nature possessed of.the ability to suffer only a small change of viscosity upon change of temperature, and to reject the compounds of naphthenic nature which do sufier such change of viscosity to 20 a more marked degree. These refining processes have enabled supply of an oil of quite desirable general characteristics, definitely far superior to any oil previously produced from mixed base or as'phaltic crudes, and superior to a like, though 25 lesser, degree over oils previously produced from paraflin base crudes.

It has been found that the solvent refined motor oils referred to above are for some reason definitely corrosive to the newer bearing metals under nor- 30 mal conditions of automotive use, sometimes resulting in bearing failure after only a few thousand miles of normal driving. It is further known that the same reaction, -viz., corrosion of alloy bearing metals such as cadmium-silver, also oc- 3 curs in good parafiinic base oils which have not been subjected to solvent refining. The higher the VI of the lubricating oil, the more pronounced is the tendency to corrosion of the kind referred to above. Generally speaking, the problem is encountered in oils having a VI of '75 or higher, and becomes imporant in oils having a VI of to or higher, and very important in oils of VI or higher. 45

It is an important object of this invention to provide means for satisfactorily inhibiting or preventing this corrosion from taking place to a serious degree. It is an object of this invention to alter or modify a highly refined motor oil, 50

normally corrosive, by the use of an additive ingredient capable of substantially inhibiting this corrosion. It is an object to provide a substantially non-corrosive motor oil of high VI. An object of this invention is to provide an additive reagent or ingredient capable of inhibiting the corrosive properties of these oils. The production of solvent refined oils of low corrosive properties under conditions of automotive use is a major object of this invention, as well as the method of production of such oils which couple high viscosity index with low tendency to corrosion.

We have found that hydrocarbon oils of the classes defined above can be stabilized in the respects above indicated by the addition thereto of small amounts of compounds selected from the class of aryl phosphites, having the general formula (AlO)3P in which Ar designates an aryl radical, as for instance (3635, or CHaCeHs. The aryl phosphites which are suitable for the uses of this invention are as follows: Compounds of the general formula where one or more of the R's is a radical selected from the group consisting of where the R's are radicals selected from the group consisting of hydrogen, alkyl, hydroxy, halogen, aryl (such as phenyl and hydroxy phenyl), alkaryl, alkoxy, nitro, and amino and substituted amino (as phenyl or benzyl substituted). Of the above defined classes of compounds, those at present preferred for the uses of this invention are those wherein all three R's are radicals of either type (a) or (b) defined above, and wherein the Rs are either hydrogen or alkyl. Examples of specific materials which we have found especially suitable for the uses of this invention are triphenyl phosphite, tricresyl phosphites and tribetanaphthyl phosphite. Where R is alkyl, it may range from a short alkyl such as methyl to very long alkyls corresponding for example to paraffin wax. Other examples which may be mentioned of suitable compounds selected from the above defined classes are phosphites of the type defined wherein the R is derived from hydroquinone, hydroxy diphenyl, guiacol, xylenol These preferred compounds may be generally described as the reaction products resulting from the reaction of trimolecular amounts of phenol or substituted phenol as defined above with a molecule of phosphorous trichloride (P013). As an example of this preparation, three molecular amounts of phenol may be mixed with one molecular amount of phosphorous trichloride, and heated to about C. until the evolution of HCl gas ceases, indicating completion of the reaction. The reaction mixture may then be heated to about C. under a pressure of 1 mm. mercury to free it completely of HCl gas and the like.

If it is desired, the product may be fractionally distilled under the same pressure. to yield a distiliate boiling from 205 to 215 C; at 2 mm. mercury, and consisting substantially of triphenylphosphite. (B. P. 209-210 C. at 2 mm. Hg). 5 Similar methods of preparation may be used for preparation of homologues, for example using ortho-cresol as starting ingredient for the production of triorthocresylphosphite. These compounds are clear oils of light color and are freely l0 miscible with hydrocarbon oils. When so mixed they do not darken nor deepen the color of the oils and show no tendency to separate under the normal conditions of storage and use.

Moderately refined oils, when subjected to ox- 5 idizing conditions in the absence of an effective inhibitor, yield both acidic compounds and sludges, tending to darken in color and to become corrosive. The inhibitory efiect of the arylphosphites may We demonstrated by the following exemplary test data. In these tests a moder-' ately refined hydrocarbon oil having a Saybolt viscosity of 152 seconds at 100 F. and a flash point of 385 F. was heated for three days at 230 F. in the presence of copper with exposure to air. The following table shows color. color after aging, and neutralization number of aged oil for an oil blank, and for oils containing stated amounts of triphenylphosphite and of triorthocresyl phosphite. 30

Table I.-Moderately refined oils Co or (Lovibond) Before After aging a n Oil alone 50 Oil+0.05% triphenylphosphite Oil-+0.10% triphenylphosphite Oil+0. 10% triorthocresylphosphite.

raw-

It is thus evident that quite minute amounts of 55 these compounds are capable of effectively protecting oils of this kind from the deteriorating effects of oxidation.

- Oils of the motor oil classes are also prone to oxidation with the formation of corrosive acidic 60 compounds, sludges, and the like. The arylphosphites contemplated by this invention are capable of effecting an inhibitive action in these oils as well, as is demonstrated by the following tests. 7 In these tests, 30 grams of oil were heated to 347 F. for 22 hours. Suspended in the oil was a carefully weighed piece of cadmium-silver alloy bearing metal. A jet of air (2000 ml. per hour) was so directed into the oil as to strike the metal. 7 Tests were run on an oil blank and on oil containing various percentages of the several aryl phosphites listed in the table. The oil used was a solvent refined motor oil of SAE 20 grade, viscosity 56 seconds Saybolt at 210 F. The loss i weight of the metal and the neutralization number of the used oil are reported.

Table II Loss in weight N. N. of of metal used oils mgs.

83f?? 'H""I"H"'HEB 8 f? a trip eny p osp l Oil+0 tripbenylphosphi 0 0.8 01l+0 tripheny1phbsph1te. l 0. 5 O1l+0 25% triorthocresylphosphlte l 0. 6 Oil+0.10% trlorthocresylphosphlte" 0 0. 4 Oil alone 69 2. 3 Oil+0.10% of a phosphite made from a mixture of o-m-p cresols 2 0. 4 Oil alone 23 l. 0 0il+0.l0% tribetanaphthylphosphite 0 0. 4 Oil alone 19 l. 6 0il+ 0.l0% triphospbite oi hydroqulnona.-. 8 0. 4

From these results it is seen that arylphosphites of this invention are quite effective in protection of moderately refined lubricants of the nature of motor oils against oxidation and specifically against corrosion of bearing metals of the cadmium-silver type.

Highly refined oils of the non-sludging or white oil type and of the transformer oil type are likewise subjected to conditions of use wherein the formation of acidic or corrosive products of oxidation is detrimental. A convenient method of testing the efiect of inhibitive compounds in such cases is the so-called German tar test. In this test, as reported below, an oil that had been highly refined by successive treatments with 98% sulfuric acid and 104% sulfuric acid, and having in finished form a specific gravity of 0.885, a viscosity of 66 seconds Saybolt at 104 F. and a flash point of 320 F., was oxidized at 248 F. by bubbling oxygen gas through it for '70 hours. The amount of oxidized material extractable by means of alcoholic sodium hydroxide reported as tar is indicative of the degree of oxidation. The tests reported include an oil blank and the oil inhibited with triphenylphosphite, a tricresylphosphite, and tribetanaphthylphosphite.

From the above data it is apparent that these compounds are competent stabilizers for the oils of the more highly refined classes as well.

The amount of the stabilizing ingredient to be used will vary with the nature of the oil to be stabilized and with the use to which it will be put. In general, effective stabilization will be obtained in the oils of the class herein discussed with not in excess of 2% of arylphosphites, usually not more than 1%. For most common uses, effective stabilization may be had with from 0.05% to 0.50% of these compounds.

In the claims, where the term "hydrocarbon oils of relatively high boiling point" or the equivalent thereof is used, it is intended to mean any and include all hydrocarbon mineral oil products normally used as lubricants or for electrical insulating purposes. It includes oils with an S. U. V. of 50 seconds at 100 F. or higher, or a flash point greater than 200 F. (Cleveland open cup). This term, in effect, is used in contradistinction of gasolines, kerosenes, and the like.

We claim:

1. A method of lubricating bearing surfaces in internal combustion engines when subjected to conditions of operation which comprises maintaining between bearing surfaces, one of which is an alloy formed chiefly of a metal selected from the class consisting of cadmium and copper, a film of lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode the aforesaid alloy, and maintaining the effectiveness of the lubricating oil by incorporating therein aryl phosphite in a small but sufficient proportion substantially. to retard the corrosion.

2. A method of lubricating bearing surfaces in internal combustion engines when subjected to conditions of operation which comprises maintaining between bearing surfaces, one of which is an alloy formed chiefly of a metal selected from the class consisting of cadmium and copper, a film of lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode the aforesaid alloy, and maintaining the effectiveness of the lubricating oil by incorporating therein from 0.1% to 1.0% of aryl phosphite suflicient substantially to retard the corrosion.

3. A method of lubricating bearing surfaces which comprises maintaining between bearing surfaces, one of which is an alloy selected from the class consisting of cadmium-silver, cadmiumnickel, and copper-lead alloys, a film of lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode the aforesaid alloy, and maintaining the effectiveness of the lubricating oil by incorporating therein aryl phosphite in a small but suflicient proportion substantially to retard the corrosiou.

4. A method of lubricating bearing surfaces which comprises maintaining between the bearing surfaces, one of which contains a characterizing proportion of cadmium, silver, nickel, copper or lead, a film of lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode the aforesaid surface, and maintaining the effectiveness of the lubricating oil by incorporating therein aryl phosphite in a small but suflicient proportion to substantially retard the corrosion.

5. A method of lubricating bearing surfaces which comprises maintaining between the bearing surfaces, one of which contains a characterizing proportion of cadmium, silver, nickel, copper or lead, a film of lubricating oil which initially produces an effective lubricating action but which would normally tend tocorrode the aforesaid surface, and maintaining the efiectiveness of the lubricating oil by incorporating therein tribetanaphthyl phosphite in a small but sufficient proportion to substantially retard the corrosion.

6. A method of lubricating bearing surfaces which comprises maintaining between the bearing surfaces, one of which contains a characterizing proportion of cadmium, silver, nickel, copper or lead, a film of lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode the aforesaid surface, and maintaining the effectiveness of the lubricating oil by incorporating therein a compound or the general formula FCC-R I \O-R where the R's are radicals selected from the group consisting of and r retard the corrosion.

7. A method of lubricating bearing surfaces which comprises maintaining between the bearing surfaces, one of which contains a characterizing proportion of cadmium, silver, nickel, copper or lead, a film of lubricatingoil which initially produces an efie'ctive lubricating action but which would normally tend to corrode the aforesaid surface, and maintaining the efiectiveness oi the lubricating oil by incorporating therein a compoundof the general formula /OR PIC-R 0-11 in which the R's are identical and each consists of a radical oi the general formula l small but sufiicient proportion to substantially retard the corrosion.

ROBERT c. MORAN. WILLIAM L. EvERs. EVERETT w. FULLER.

CERTIFICATE OF CORRECTION.

Patent No. 2,058,343. I October 20. 1936;

ROBERT c. MORAN, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, lines 29 and 49, for "R's" read Rs; lines 42 and '51, for "R's" read B's; and second column, line 45, in the heading to the table, for "Co or" read Color; page 4, first column, line '7, claim 6, and second column, line 13, claim 7,. for "R's" read Rs; same page, first column, line 22, claim 6, and second column, line 21, claim '7, for "R's read B's; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 23rd day of February, A. D. 1937.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

